1. Field of the Invention
The present invention relates generally to an automotive body structure and more particularly to an automotive rear body structure capable of effectively absorbing the kinetic energy of an impact load exerted from the rear, for example, when a rear-end collision has occurred.
2. Description of Related Art
FIGS. 13 and 14 depict a conventional automotive rear body structure after a rear-end collision has occurred in which the rear of an automotive vehicle is struck by another automotive vehicle.
The structure shown in FIGS. 13 and 14 comprises a pair of longitudinally extending side sills (a) disposed on respective sides of a vehicle body, a pair of rear wheels (b1) and (b2) disposed rearwardly of respective side sills (a), a pair of longitudinally extending rear frames (c) disposed inwardly of respective side sills (a), and a rear suspension cross member (d) extending transversely between both the rear frames (c) and having opposite ends secured thereto. A pair of outwardly extending suspension arms (e) are secured at their inner ends to the rear suspension cross member (d) and at their outer ends to hubs of the rear wheels (b1) and (b2), respectively. A pair of longitudinally extending trailing arms (f) are secured at their front ends to the rear frames (c) and at their rear ends to the hubs of the rear wheels (b1) and (b2), respectively. Rearwardly of the rear suspension cross member (d) are provided a silencer (g) and a spare tire housing (m). Forwardly of the rear suspension cross member (d) is provided a fuel tank (j) carried by bands (k).
The silencer (g) is provided with tail pipes (h) extending rearwardly therefrom and is connected to an exhaust gas pipe (i) extending generally rearwardly from an engine. Rear ends of the rear frames (c) are connected to a transversely extending rear bumper (n).
The rear frames (c) are bent inwardly at their respective locations where they are connected to the rear suspension cross member (d) and are provided with generally rearwardly upwardly extending respective kick-up portions (c1) formed forwardly of their inwardly bent portions.
In this conventional automotive rear body structure, in the event of a rear-end collision, the tail pipes (h) of the silencer (g) are subjected to little deformation, as shown in FIGS. 13 and 14, and the kinetic energy of an impact load caused by the collision is transmitted to the silencer (g) without damping. Accordingly, the silencer (g) is moved forwardly, thereby pushing and deforming the rear suspension cross member (d). At the same time, the rear frames (c) are pushed forwardly via the rear suspension cross member (d). As a result, the upwardly bent kick-up portions (c1) of the rear frames (c) are subjected to stress concentration, which may cause these portions to be deformed or broken. The forward deformation of the rear suspension cross member (d) occasionally causes deformation of the fuel tank (j), and consequently, there arises a problem in that a considerably deformed portion (p) would be destroyed.